public abstract class Sphere implements Shape {
	protected float R;

	abstract public String getColor();

	protected Sphere(float radius) {
		this.R = radius;
	}

	public float volume() {
		return 4.0f / 3.0f * (float)Math.PI * (float)Math.pow(this.R, 3);
	}

	@Override
	public String toString() {
		return "I'm a sphere";
	}
}
